The present invention relates to a conveyance receiver for supporting and conveying a ceramic honeycomb formed article subjected to extrusion forming. More specifically, the present invention relates to a conveyance receiver capable of conveying a clayey honeycomb formed article without being deformed and a conveyance apparatus and a conveyance method using the conveyance receiver.
Conventionally, as an example of a forming method of a honeycomb formed article, there has been known an extrusion forming method. In this method, a die having a desired shape is attached to the extrusion outlet of an extruder where the extrusion direction is set in a horizontal direction, and a ceramic material put in the extruder is successively extruded from the die to form a honeycomb formed article having a columnar shape. The extruded honeycomb formed article having a columnar shape is carried over the conveyance path with being held by a conveyance receiver and subjected to each of the steps of cutting, drying, firing, and the like, to give a honeycomb structure as a final form.
Here, since a honeycomb formed article right after the extrusion forming is clayey, it is very soft and easily deformed. In order to obtain a final formed article having good quality, it is necessary to convey the honeycomb formed article right after the extrusion forming to the following steps with supporting it lest deformation should be caused. In particular, the receiver directly supporting a cylindrical honeycomb formed article generally has a depressed top portion so as to correspond with the outer peripheral shape of the cylindrical honeycomb formed article. However, since high shape accuracy is necessary to suppress the deformation of the formed article to be supported, securement of easy and accurate processability of the material used for the receiver has conventionally been one of important conditions. For example, in the case that the depressed portion of the conveyance receiver is formed to be smaller than the outer periphery size of a honeycomb formed article, collapse or deformation is caused in the formed article when it is placed on the receiver. On the other hand, in the case that the depressed portion of the conveyance receiver is formed to be larger than the outer periphery size of a honeycomb formed article to form a gap between the outer periphery of the formed article placed on the receiver and the depressed portion of the receiver, deformation is caused in the honeycomb formed article by bias of contact pressure between the outer periphery of the formed article and the inner surface of the depressed portion, movement of the formed article upon conveyance, and the like, and a good final product cannot be obtained. That is, in order to reduce the defect incidence, it is necessary that the depressed shape of the conveyance receiver corresponds with the outer peripheral shape of the honeycomb formed article to be supported with high accuracy, and a material where such accurate processing into a depressed shape is realized has to be employed.
In addition, since a honeycomb formed article right after the extrusion contains much water, a material used for the receiver has conventionally been required to satisfy various conditions such as releasability and hygroscopicity. For example, when a clayey honeycomb formed article having high humidity sticks to the conveyance receiver, release from the receiver is hard, which may cause deformation or collapse of the formed article. In addition, even in one honeycomb formed article, water hardly evaporates from the portion closely adhering to the receiver, while water easily evaporates from the portion in contact with air without adhering to the receiver. Therefore, water content inside the formed article is uneven, which may cause a crack in the final product. That is, in the formed article, it is necessary to secure minimum evaporation even in the portion in contact with the receiver. Thus, as the material for the receiver, a material in appropriate conditions should be employed lest the honeycomb formed article and the receiver should adhere to each other.
As described above, selection of a material having desired properties has conventionally been a serious problem for a conveyance receiver of a honeycomb formed article. For example, JP-A-2002-046856 discloses a conveyance receiver for a honeycomb formed article, where a Styrofoam support portion is provided on an aluminum base with the support portion being covered with a buffer material. In addition, JP-A-2002-103325 discloses a foamed article provided on a base plate having high strength, and JP-A-2004-142160 discloses a conveyance receiver of a low repulsion material capable of easy transformation.
However, in a conveyance receiver disclosed in JP-A-2002-046856, because of the properties of the material of Styrofoam, there is a limitation in processing accuracy. Therefore, upon processing into a depressed shape, variance in shape accuracy is caused among the receivers to have a problem of causing interindividual differences. In addition, also the variance in thickness of an adhesive for bonding the buffer material and the support portion serves as a cause of interindividual differences in the depressed shape among the receivers. In addition, since each of the materials employed for the conveyance receivers disclosed in JP-A-2002-103325 and JP-A-2004-142160 is a foaming material having cushioning properties and relatively low density and low hardness, it is hard to realize high processing accuracy as in the case of JP-A-2002-046856.